Semiconductor device for detection of radiation and method of producing a semiconductor device for detection of radiation

Description

[0001] US 2007/249095 A1 discloses a semiconductor package including an infrared filter, which is bonded to a semiconductor wafer. The IR filter is obtained by applying a suitable filter layer on a glass sheet having the same dimensions as the wafer. The glass sheet is bonded to the wafer with the IR filter layer on the side facing towards the wafer. The wafer is thinned, so that the resulting total thickness of the wafer and the filter is not greater than the initial thickness of the wafer. Via holes are formed through the wafer from the side opposite the filter to contact pad electrodes that are located between the wafer and the filter.

[0002] US 2009/0256216 A1 discloses a wafer level chip scale package including a die substrate containing electronic circuits. Through-silicon vias are formed leading through the substrate and electrically connecting the electronic circuits to the bottom surface of the die substrate. An infrared sensor is coupled to the top surface of the die substrate, and a sensor aperture is formed in a protective encapsulant layer arranged above the sensor.

[0003] The formation of through-silicon vias in a semiconductor substrate is also described in WO 2010/006916 A1, US 2010/0314762 A1, WO 2010/081603 A1 and WO 2011/039167 A1.

[0004] Production methods using temporary bonding are described in US 2009/0218560 A1, DE 101 56 465 C1 and US 2005/0173064 A1.

[0005] US 2010/0327383 A1 discloses a semiconductor device comprising imaging elements with photodiodes and a through-electrode in a through-hole which penetrates the silicon substrate. Copper interconnection layers are embedded in silicon oxide interlayer insulating films. A base layer is formed on the uppermost interlayer insulating film and interconnection layer. Color filters are arranged on the base layer to correspond to the imaging elements.

[0006] US 2011/0024858 A1 discloses a solid-state imaging device comprising light-sensing portions in a semiconductor substrate, a wiring portion including a plurality of silicon oxide interlayer insulating films and wiring patterns on the substrate 11, and a through-via in the substrate. An organic planarizing film is arranged on the interlayer insulating film, and a color filter layer is arranged on the planarizing film.

[0007] WO 2009/084701 A1 discloses a semiconductor device comprising a silicon substrate, a plurality of imaging elements formed in element regions on the substrate surface, an SiO₂ interlayer dielectric film on the substrate surface, a base layer on the interlayer dielectric film, color filters on the base layer opposite the imaging elements, and an internal electrode, which is arranged on the conductor layer of a through-hole electrode penetrating the substrate and is electrically connected to the imaging element or to a peripheral circuit.

[0008] US 7,248,297 B2 discloses an integrated color pixel with at least one integrated metal filter adapted to obtain the desired wavelength responsivity.

[0009] WO 2012/007147 A1 discloses an optical bandpass filter system including a combination of a bandpass filter comprising a first nanostructured metallic layer and a bandstop filter comprising a second nanostructured metallic layer.

[0010] It is an object of the present invention to disclose a semiconductor device for detection of radiation which is suitable for a small overall package size.

[0011] This object is achieved with the semiconductor device according to claim 1 and with the method of producing a semiconductor device according to claim 6. Embodiments and variants derive from the dependent claims.

[0012] The semiconductor device for detection of radiation comprises a semiconductor substrate with a main surface, a dielectric layer comprising at least one compound of a semiconductor material and an intermetal layer, an integrated circuit including at least one component sensitive to radiation, a wiring of the integrated circuit, an electrically conductive through-substrate via contacting the wiring, and an optical filter element arranged immediately on the dielectric layer above the component sensitive to radiation. The dielectric layer is arranged on or above the main surface, the integrated circuit is arranged in the substrate at or near the main surface, and the wiring is arranged in the intermetal layer.

[0013] The dielectric layer comprises an intermetal layer, and the wiring is arranged in the intermetal layer.

[0014] In an embodiment of the semiconductor device the intermetal layer comprises silicon dioxide, and the optical filter element is arranged immediately on the intermetal layer.

[0015] The dielectric layer comprises a passivation layer at least above the through-substrate via, the passivation layer comprises a dielectric material that is different from the intermetal layer, and the wiring is arranged between the main surface and the passivation layer.

[0016] The passivation layer is arranged in or on the intermetal layer, the passivation layer comprises an opening above the component sensitive to radiation, so that the intermetal layer is free from the passivation layer in the opening, and the optical filter element is arranged on the intermetal layer above or in the opening of the passivation layer.

[0017] In a further embodiment of the semiconductor device the optical filter element comprises a first structured filter layer providing an interference filter and a second structured filter layer providing at least one colour component of an RGB filter.

[0018] In a further embodiment of the semiconductor device an integrated optical filter layer is arranged in the dielectric layer, so that the integrated optical filter layer is between the component sensitive to radiation and the optical filter element and is at a distance from the optical filter element.

[0019] In a further embodiment of the semiconductor device, metal layers of the wiring and the integrated optical filter layer are arranged in the intermetal layer, and the integrated optical filter layer is formed in a metal layer that is arranged in the intermetal layer.

[0020] In a further embodiment of the semiconductor device the substrate and the dielectric layer together comprise a thickness (d) of less than 250 µm.

[0021] The method of producing a semiconductor device for detection of radiation comprises the steps of providing a semiconductor substrate with an integrated circuit including at least one component sensitive to radiation at or near a main surface, arranging a dielectric layer comprising at least one compound of a semiconductor material on or above the main surface, arranging a wiring of the integrated circuit in the dielectric layer, forming an electrically conductive through-substrate via contacting the wiring from a rear surface opposite the main surface, and arranging an optical filter element immediately on the dielectric layer above the component sensitive to radiation.

[0022] In a variant of the method the optical filter element is arranged on the dielectric layer before the through-substrate via is formed.

[0023] In a further variant of the method the optical filter element is arranged on the dielectric layer after the through-substrate via is formed.

[0024] The dielectric layer is formed to include an intermetal layer and a passivation layer, the passivation layer being provided with an opening above the component sensitive to radiation, the intermetal layer being free from the passivation layer in the opening, and the optical filter element is arranged on the intermetal layer and in the opening of the passivation layer.

[0025] In a further variant of the method an integrated optical filter layer is arranged in the dielectric layer, and the integrated optical filter layer is formed as a nanooptics filter.

[0026] In a further variant of the method the integrated optical filter layer is formed before the through-substrate via is formed.

[0027] The following is a detailed description of examples of the semiconductor device and of the appertaining method of production.

Figure 1 is a cross section of an embodiment, not making part of the invention, of the semiconductor device for detection of radiation.

Figure 2 is a cross section of a further embodiment of the semiconductor device.

Figure 3 is a cross section of an embodiment comprising an integrated filter layer.

Figure 4 is a cross section of a further embodiment comprising an integrated filter layer.

Figure 5 is a cross section of a semiconductor device comprising two structured filter layers.

Figure 6 is a cross section of a further embodiment comprising two structured filter layers.

Figure 7 is a cross section of a further embodiment comprising two structured filter layers.

Figure 8 is a cross section of a semiconductor device comprising an array of photodiodes.

Figure 9 is a cross section of an intermediate product of a production method for the embodiment according to Figure 3.

Figure 10 is a cross section according to Figure 9 after the application of a first handling wafer and further process steps.

Figure 11 is a cross section according to Figure 10 after the application of a second handling wafer.

Figure 12 is a cross section according to Figure 11 after the removal of the first handling wafer and further process steps.

Figure 13 is a cross section according to Figure 9 for the embodiment according to Figure 4.

Figure 14 is a cross section according to Figure 13 after the application of a handling wafer.

Figure 15 is a cross section according to Figure 14 after further process steps and before the removal of the handling wafer.

[0028] Figure 1 is a cross section of an embodiment of the semiconductor device for detection of radiation. A semiconductor substrate 1, which may be a silicon wafer, for instance, is provided with an integrated circuit 2 comprising at least one component sensitive to radiation 3 at or near a main surface 11 of the substrate 1. This can be a single device or a plurality of devices that are singulated by a later wafer dicing process. The integrated circuit 2 may further comprise a CMOS circuit or the like. The component sensitive to radiation 3 may be provided for optical applications, for instance, such as ambient light sensing, color sensing and proximity sensing, as well as for other applications including the detection of incident radiation. In particular, the component sensitive to radiation 3 may be a photodiode.

[0029] A wiring 4 is formed above the main surface 11 to provide electric connections to terminals of the integrated circuit 2 and, in particular, of the component sensitive to radiation 3. The wiring 4 may be formed by structured metal layers embedded in an intermetal dielectric, for example. At least one through-substrate via 5 comprising a metallization 15 penetrates the substrate 1 in order to connect a contact area 16 of the wiring 4 with a rear wiring 17, which may be a redistribution layer, for instance, or the like. The rear wiring 17 may be a patterned metal layer, for example.

[0030] A dielectric layer 6 is arranged on the main surface 11 and serves to accomodate a filter structure above the component sensitive to radiation 3. The dielectric layer 6 comprises at least one compound of a semiconductor material, in particular an oxide or nitride of a semiconductor material like silicon, especially SiO₂, for example. In the embodiment according to Figure 1 the dielectric layer 6 comprises intermetal layers 8 of the wiring 4.

[0031] A passivation layer 9, which may be a further dielectric material like a nitride of the semiconductor material, especially Si₃N₄, for example, may optionally be arranged within the dielectric layer 6 as shown in Figure 1. In the present invention, the passivation layer 9 has an opening 13 above the component sensitive to radiation 3, so that the passivation layer 9 may comprise a material that might lead to unwanted optical interferences of the radiation, which is however avoided by the opening 13 in the passivation layer 9. In an example not making part of the invention, the passivation layer 9 may instead be an entire layer, as indicated in Figure 1 by the broken lines.

[0032] A dielectric layer 18 on the rear side 10 of the substrate 1 and/or on the sidewall of the through-substrate via 5 may be provided to insulate the metallization 15 and/or the rear wiring 17 from the semiconductor material. The rear wiring 17 may be provided with bumps 19 for external electric connection and with a passivation 20 covering the areas of the rear side 10 that are not used for the external electric connection. The passivation 20 may be a deposited silicon nitride layer, for example, and may especially be applied to provide a moisture barrier and/or a mechanical protection for the metal of the rear wiring 17 and the through-substrate via 5.

[0033] The filter structure comprises at least one structured filter element, especially an optical filter element, which is a structured filter layer 7 arranged immediately on the dielectric layer 6 and may especially comprise a stack of different partial layers. Examples of such filters are ultraviolet cut-off filters, infrared cut-off filters, photopic filters, color filters, band-pass filters and any combination thereof. A transparent thin coating layer 14, which may typically be less than 30 µm thick, may be applied above for protection and/or for an optical modification.

[0034] It is an essential feature of the semiconductor device that the filter structure is not provided in or on a layer of glass and is not covered by a layer of glass, and hence no further substrate is necessary for the accomodation of the filter structure. This is important, because a substantial reduction of the overall height of the device is thereby achieved, which yields a small package size. The substrate 1 and the dielectric layer 6 may together comprise a thickness t₁ of less than 250 µm or even less than 200 µm. Therefore this semiconductor device allows the manufacture of very thin chip scale packages and thus offers considerable advantages in system integration, especially for consumer products. Furthermore, the filter structure is provided by a structured filter layer 7, which may be confined to the area of the component sensitive to radiation 3.

[0035] Figure 2 is a cross section of a further embodiment of the semiconductor device for detection of radiation. The elements of the embodiment according to Figure 2 that correspond to similar elements of the embodiment according to Figure 1 are designated with the same reference numerals. The embodiment according to Figure 2 comprises a structured filter layer 7, which is arranged on the dielectric layer 6 and at least partially in the opening 13 of the passivation layer 9. In this embodiment there is no portion of the dielectric layer 6 above the passivation layer 9. A coating layer 14 may be applied on the passivation layer 9 and on the structured filter layer 7. In the embodiment according to Figure 2, the substrate 1 and the dielectric layer 6 may together comprise a thickness t₂ of less than 250 µm or even less than 200 µm. Figure 3 is a cross section of a further embodiment comprising an integrated filter layer 12. The elements of the embodiment according to Figure 3 that correspond to similar elements of the embodiment according to Figure 1 are designated with the same reference numerals. The integrated filter layer 12 is suitably structured to cover the component sensitive to radiation 3 and may be arranged in an intermetal layer 8 or between intermetal layers 8, in which the wiring 4 is embedded. The integrated filter layer 12 may especially be formed as a nanooptics filter, which may be structured in the wiring 4 or, preferably, formed by a dedicated further metal layer, which may be arranged in an intermetal layer 8 or between intermetal layers 8. The integrated filter layer 12 may be arranged at a distance d from the structured filter layer 7. In the embodiment according to Figure 3, the passivation layer 9 is provided with an opening 13 in the area above the component sensitive to radiation 3. The passivation layer 9 may instead be a continuous entire layer according to the alternative embodiment not making part of the invention, indicated in Figure 1 by broken lines.

[0036] Figure 4 is a cross section of a further embodiment comprising an integrated filter layer 12. The elements of the embodiment according to Figure 4 that correspond to similar elements of the embodiment according to Figure 2 are designated with the same reference numerals. In the embodiment according to Figure 4, the structured filter layer 7 is arranged on the intermetal layer 8 in an opening 13 of a passivation layer 9, similar to the embodiment shown in Figure 2. The integrated filter layer 12 may be arranged in the intermetal layer 8 or between intermetal layers 8 at a distance d from the structured filter layer 7 according to the embodiment shown in Figure 3.

[0037] In both embodiments according to Figures 3 and 4 the integrated filter layer 12 is optional. The structured filter layer 7 and the integrated filter layer 12 may have different properties and may especially provide two different types of optical filters. The structured filter layer 7 may be a colour filter, for instance, which is transparent for wavelengths in a selected range of the spectrum, like red, green or blue light. The colour filter may preferably be formed from an organic material, or it may be an interference filter. An interference filter can be formed by a sequence of layers comprising at least two different dielectric materials. The optical properties of the filter derive from the properties of the layers, and different layer sequences may consequently result in different types of interference filters like infrared filters, ultraviolet filters or colour filters, for example. Different types of interference filters may be integrated on the same chip.

[0038] The semiconductor device is especially suitable for a production method in which a plurality of devices are produced on the same wafer for a chip scale package. In this case the filter structure may vary between the semiconductor devices that are produced on the same chip. It is thus also possible to produce a variety of sensor devices on the same chip, the individual devices being adapted for the detection of different radiation and/or having different sensitivities, for example.

[0039] Figure 5 is a cross section of a semiconductor device with a structured filter layer 7 that comprises a first layer 28 and a second layer 29. The elements of the device according to Figure 5 that correspond to similar elements of the embodiment according to Figure 1 are designated with the same reference numerals. The first layer 28 may be an interference filter, for instance, and the second layer 29 may be an optical colour filter, for instance, especially a colour component of an RGB filter. In the device shown in Figure not making part of the present invention, an entire passivation layer 9, which is optional, is embedded in the dielectric layer 6. In the present invention, the passivation layer 9 is provided with an opening above the component sensitive to radiation 3.

[0040] Figure 6 is a cross section of a further embodiment with a structured filter layer 7 that comprises a first layer 28 and a second layer 29. The elements of the embodiment according to Figure 6 that correspond to similar elements of the embodiment according to Figure 5 are designated with the same reference numerals. The embodiment according to Figure 6 also comprises a passivation layer 9 arranged in the dielectric layer 6. The difference between the embodiment according to Figure 6 and the embodiment according to Figure 5 is the opening 13 in the passivation layer 9 above the component sensitive to radiation 3. The opening 13 allows the passivation layer 9 to comprise a material that might lead to undesirable optical interferences. Such a material would not affect the incidence of the radiation in the area of the opening 13.

[0041] Figure 7 is a cross section of a further embodiment with a structured filter layer 7 that comprises a first layer 28 and a second layer 29. The embodiment according to Figure 7 has a filter structure that is similar to the filter structure of the embodiment according to Figure 2. The elements of the embodiment according to Figure 7 that correspond to similar elements of the embodiment according to Figure 2 are designated with the same reference numerals. The first layer 28 of the structured filter layer 7 may be an interference filter, for instance, and the second layer 29 of the structured filter layer 7 may be an optical colour filter, for instance, especially a colour component of an RGB filter. The structured filter layer 7 may be arranged immediately on the intermetal layer 8 in the opening 13 of the passivation layer 9 above the component sensitive to radiation 3.

[0042] Figure 8 is a cross section of a device comprising an array of photodiodes each comprising a separate portion of the structured filter layer 7. The distances between the photodiodes and the areas that are occupied by the through-substrate vias 5 may vary. The structured filter layer 7 may comprise a single layer or a sequence of layers, especially a double layer as shown in Figure 8 as an example. If the first layers 28 or the second layers 29 of the portions of the structured filter layer 7 are different layers of an RGB filter, the array may be used to detect a coloured image. In the device according to Figure 8, the passivation layer 9 is an entire layer, but , in the present invention, the passivation layer 9 is instead provided with openings 13 above the components sensitive to radiation 3 forming the array, as shown in Figure 7.

[0043] Figure 9 is a cross section of an intermediate product of a production method for the embodiment according to Figure 3. The intermediate product may have a thickness t₃, as indicated in Figure 9 by the vertical double-headed arrow, of typically 730 µm, for example. The substrate 1 is provided with the integrated circuit 2 comprising at least one component sensitive to radiation 3 at or near a main surface 11 of the substrate 1. One or more metallization levels of the wiring 4 may be produced according to a conventional CMOS process within the dielectric layer 6, which may comprise intermetal layers 8, especially silicon oxide forming an intermetal dielectric, for example. At this stage of the manufacturing process, integrated filter layers 12, in particular nanooptics filters, may also be arranged in the dielectric 6.

[0044] A passivation layer 9 may be formed, in particular from silicon nitride, within the dielectric layer 6 and can optionally be opened with a masked plasma etch above the component sensitive to radiation 3. This may be advantageous in order to avoid wavelength dependent variations of the intensity of the radiation which reaches the component sensitive to radiation 3. The surface of the dielectric layer 6 can be planarised with chemical mechanical polishing (CMP) steps, for instance. A local waviness, unevenness or roughness of the surface is preferably kept within a level range of less than 6 nm.

[0045] Figure 10 is a cross section according to Figure 9 after the bonding of a first handling wafer 21 on the dielectric layer 6 and the production of the through-substrate via 5 and the rear wiring 17. The first handling wafer 21 may be a silicon wafer with a thickness t₄ of typically about 725 µm, for example. If the dielectric layer 6 is silicon oxide, a thin layer of thermal oxide 24, having a typical thickness of 400 nm, for example, is preferably formed on a main surface of the first handling wafer 21 by a thermal oxidation. The first handling wafer 21 can thus be bonded directly to the dielectric layer 6 as shown in Figure 10. The first handling wafer 21 can instead be bonded to the dielectric layer 6 by means of an adhesive, which takes the place of the thermal oxide 24.

[0046] After the first handling wafer 21 has been bonded to the intermediate product shown in Figure 9, the substrate 1 is thinned from the rear surface 10. The thinning may be performed by conventional grinding and polishing steps. The thickness of the substrate 1 is thus preferably reduced to less than 250 µm or even less than 200 µm. The first handling wafer 21 improves the mechanical stability of the thinned substrate 1.

[0047] A dielectric layer 18, which may be a silicon oxide layer, is preferably deposited on the rear surface 10 of the thinned substrate 1. The dielectric layer 18 is structured, which may be performed by a conventional photolithographic process using a resist mask. The produced structures are preferably aligned to structures at the main surface 11, especially to structures of the integrated circuit 2.

[0048] A via hole for the through-substrate via 5 is etched in the substrate 1, and the structured dielectric layer 18 is preferably used as a hard mask during the etching process.

[0049] The sidewall of the via hole is optionally covered with silicon oxide. The contact area 16 of the wiring 4 is uncovered at the bottom of the via hole, suitably by an anisotropic spacer etch leaving the sidewall covered with the silicon oxide. This spacer etch removes the oxide selectively, so that the thickness of the metal layer of wiring 4 underneath is not significantly changed. Then the metallization 15 is applied.

[0050] The metallization 15 may be produced by a deposition of a thin barrier layer of titanium nitride or tantalum nitride, for instance, and a subsequent deposition of a metal layer. A layer of tungsten is preferably applied as the metal layer in conjunction with a barrier layer of titanium nitride, and a layer of copper is preferably applied in conjunction with a barrier layer of tantalum nitride. The metal layer is anisotropically etched, so that mainly the sidewall of the via hole remains covered with the metallization 15.

[0051] The rear wiring 17 may be produced by sputtering a further metal layer, which may be aluminum, for example. An area in which the further metal layer overlaps with the metallization 15 is favourable to ensure an electric connection of low resistivity between the metallization 15 and the further metal layer. The electric connection to the metallization 15 is maintained when the further metal layer is subsequently patterned into the structure intended for the rear wiring 17. A resist mask defining the pattern can be formed in a conventional photolithography step by applying a resist by means of spray-coating or by laminating a thin film resist on the rear surface 10, a subsequent masked exposure to ultraviolet light and development. The further metal layer is structured by an etching step, particularly by a plasma etching step, using the resist mask, which is afterwards removed.

[0052] The passivation 20, which may comprise a silicon oxide layer and a silicon nitride layer, for example, can then be applied preferably by using plasma enhanced chemical vapour deposition (PECVD), whereby the sidewall of the through-substrate via 5 is preferably also coated. In a further photolithography and a subsequent further etching step, the passivation 20 is opened at locations provided for the bumps 19, which can be formed by applying solder balls on the uncovered pads or contact areas 27 of the rear wiring 17, for example.

[0053] Figure 11 is a cross section according to Figure 10 after the application of a second handling wafer 22 on the side opposite the first handling wafer 21. The second handling wafer 22 allows to remove the first handling wafer 21 without impairing the mechanical stability of the substrate 1. The second handling wafer 22 may have a thickness t₅ of typically about 725 µm, for example, and may be a further silicon wafer. A connection layer 25 may be formed by a thermoplast coating on a surface of the second handling wafer 22 before it is adhesively bonded to the passivation 20 at an elevated temperature under mechanical pressure. A zone bonding method known per se can be used alternatively. The pads or contact areas 27 that are provided for the bumps 19 are preferably uncovered by forming openings in the passivation 20 before the second handling wafer 22 is bonded, as shown in Figure 11.

[0054] The first handling wafer 21 is then removed. If the first handling wafer 21 is a directly bonded silicon wafer, it is first ground to a residual thickness of about 40 µm. The rest of the silicon can be removed by a wet chemical spin etch process, which stops on the thermal oxide 24 with a high selectivity. If the first handling wafer 21 is instead adhesively bonded, other appropriate process steps, which are known per se in semiconductor technology, can be applied, which may include the use of a laser, for example. In this case the first handling wafer 21 is preferably a glass wafer.

[0055] Figure 12 is a cross section according to Figure 11 after the removal of the first handling wafer 21 and further process steps, in which the structured filter layer 7 and the coating layer 14 are applied on the dielectric layer 6. The structured filter layer 7 is preferably confined to an area above the component sensitive to radiation 3, while the coating layer 14 may be applied to the entire surface in order to planarize the upper surface of the device and to protect the surface from damage.

[0056] When the second handling wafer 22 has been removed and the pads or contact areas 27 of the rear wiring 17 have been uncovered, the bumps 19 are applied. An underbump metallization (UBM) of nickel and gold may be produced on the contact areas 27 by an electroless plating process, for example. Solder balls forming the bumps 19 are attached to the underbump metallization, and a thermal reflow process is subsequently performed.

[0057] Figure 13 is a cross section according to Figure 9 for the embodiment according to Figure 4. The elements of the intermediate product according to Figure 13 that correspond to similar elements of the intermediate product according to Figure 9 are designated with the same reference numerals. In this variant of the method, the structured filter layer 7 is applied after the production of the dielectric layer 6 including the wiring 4 and, if the passivation layer 9 is provided, also after the application and structuring of the passivation layer 9 comprising the opening 13. The structured filter layer 7 is applied in the opening 13 on the dielectric layer 6. As shown in Figure 13, the structured filter layer 7 can optionally surmount and overlap the edges of the passivation layer 9.

[0058] This method is favourably applicable in case that solely stacks of dielectric interference filters are required. The complete filter structure 7, 12 can be produced after the completion of the process producing the integrated circuit 2, in particular at the end of a CMOS process. In this case no planarised surface is required above the main surface 11.

[0059] Figure 14 is a cross section according to Figure 13 after the application of a third handling wafer 23, which corresponds to the first handling wafer 21 of the method previously described. The third handling wafer 23 can be bonded by means of a connection layer 26 formed of a removable thermoplast, for instance.

[0060] Figure 15 is a cross section according to Figure 14 after further process steps before the removal of the third handling wafer 23. After the third handling wafer 23 has been bonded to the intermediate product shown in Figure 13, the substrate 1 is thinned from the rear surface 10 as described above. The thickness t₂ of the substrate 1 is thus preferably reduced to less than 250 µm or even less than 200 µm. The third handling wafer 23 improves the mechanical stability of the thinned substrate 1.

[0061] A dielectric layer 18, which may be a silicon oxide layer, may be deposited on the rear surface 10 of the thinned substrate 1 and structured as described above. A via hole for the through-substrate via 5 is etched in the substrate 1, and the structured dielectric layer 18 is preferably used as a hard mask during the etching process. The sidewall of the via hole is optionally covered with silicon oxide. The contact area 16 of the wiring 4 is uncovered at the bottom of the via hole, suitably by an anisotropic spacer etch leaving the sidewall covered with the silicon oxide.

[0062] Then the metallization 15 and the rear wiring 17 are applied as described above. The passivation 20, which may comprise a silicon oxide layer and a silicon nitride layer, for example, can then be applied as described above. The passivation 20 is opened at locations provided for the bumps 19. The pads or contact areas 27 of the rear wiring 17 are thereby uncovered. The third handling wafer 23 may now be debonded by removing the connection layer 26, and the third handling wafer 23 is thus removed from the device. An underbump metallization may be provided before the bumps 19 are applied on the pads or contact areas 27. The bumps 19 can be formed by solder balls, for example.

[0063] The described semiconductor device and the appertaining production method allow the manufacture of a very small chip scale package for semiconductor devices that are intended for the detection of radiation. The overall package height can be kept smaller than about 350 µm. This is a substantial improvement in comparison with conventional packages, which are at least 500 µm thick. It is essential for this achievement that the top cover of the device is glassless, so that no second substrate is necessary to implement the filter structure. This has the further advantage that chip dicing is facilitated and the chip out rate is dramatically reduced, leading to higher yield. The resistance of the device against moisture is improved and the reliability is enhanced. A plurality of different types of filters can easily be produced on the same chip and/or on the same semiconductor wafer.

List of reference numerals

[0064] 

1

semiconductor substrate

2

integrated circuit

3

component sensitive to radiation

4

wiring

5

through-substrate via

6

dielectric layer

7

structured filter layer

8

intermetal layer

9

passivation layer

10

rear surface

11

main surface

12

integrated filter layer

13

opening of the passivation layer

14

coating layer

15

metallization

16

contact area

17

rear wiring

18

dielectric layer

19

bump

20

passivation

21

first handling wafer

22

second handling wafer

23

third handling wafer

24

thermal oxide

25

connection layer

26

connection layer

27

contact area

28

first layer of the structured filter layer

29

second layer of the structured filter layer

d

distance

t_n

thickness

Claims

1. A semiconductor device for detection of radiation, comprising:

- a semiconductor substrate (1) with a main surface (11),

- a dielectric layer (6) comprising at least one compound of a semiconductor material, the dielectric layer (6) being arranged on or above the main surface (11),

- an integrated circuit (2) including at least one component sensitive to radiation (3), the integrated circuit (2) being arranged in the substrate (1) at or near the main surface (11),

- a wiring (4) of the integrated circuit (2), the dielectric layer (6) comprising an intermetal dielectric layer (8), the wiring (4) being arranged in the intermetal dielectric layer (8),

- an electrically conductive through-substrate via (5) contacting the wiring (4), and

- an optical filter element (7) arranged immediately on the dielectric layer (6) above the component sensitive to radiation (3),

characterized in that

- the dielectric layer (6) comprises a passivation layer (9) at least above the through-substrate via (5),

- the passivation layer (9) comprises a dielectric material that is different from the intermetal dielectric layer (8),

- the wiring (4) is arranged between the main surface (11) and the passivation layer (9)

- the passivation layer (9) is arranged in or on the intermetal dielectric layer (8),

- the passivation layer (9) comprises an opening (13) above the component sensitive to radiation (3), the intermetal dielectric layer (8) being free from the passivation layer (9) in the opening (13), and

- the optical filter element (7) is arranged on the intermetal dielectric layer (8) above or in the opening (9) of the passivation layer (9).

2. The semiconductor device of claim 1, wherein
the optical filter element (7) comprises a first structured filter layer (28) providing an interference filter and a second structured filter layer (29) providing at least one colour component of an RGB filter.

3. The semiconductor device of claim 1 or 2, further comprising:

an integrated optical filter layer (12) in the dielectric layer (6), the integrated optical filter layer (12) being arranged between the component sensitive to radiation (3) and the optical filter element (7) and at a distance (30) from the optical filter element (7).

4. The semiconductor device of one of claims 1 to 3, wherein metal layers of the wiring (4) and the integrated optical filter layer (12) are arranged in the intermetal dielectric layer (8), and
the integrated optical filter layer (12) is formed in a metal layer that is arranged in the intermetal dielectric layer (8).

5. The semiconductor device of one of claims 1 to 4, wherein the substrate (1) and the dielectric layer (6) together comprise a thickness (d) of less than 250 µm.

6. A method of producing a semiconductor device for detection of radiation, as defined in claim 1, comprising:

- providing a semiconductor substrate (1) with an integrated circuit (2) including at least one component sensitive to radiation (3) at or near a main surface (11),

- arranging a dielectric layer (6) comprising at least one compound of a semiconductor material on or above the main surface (11),

- arranging a wiring (4) of the integrated circuit (2) in the dielectric layer (6),

- forming an electrically conductive through-substrate via (5) contacting the wiring (4) from a rear surface (10) opposite the main surface (11), and

- arranging an optical filter element (7) immediately on the dielectric layer (6) above the component sensitive to radiation (3),

characterized in that

- the dielectric layer (6) is formed to include an intermetal dielectric layer (8) and a passivation layer (9), the passivation layer (9) being provided with an opening (13) above the component sensitive to radiation (3), the intermetal dielectric layer (8) being free from the passivation layer (9) in the opening (13),

- the passivation layer (9) comprises a dielectric material that is different from the intermetal dielectric layer (8),

- the wiring is arranged between the main surface (11) and the passivation layer (9), and

- the optical filter element (7) is arranged on the intermetal dielectric layer (8) above or in the opening (13) of the passivation layer (9).

7. The method of claim 6, wherein
the optical filter element (7) is arranged on the dielectric layer (6) before the through-substrate via (5) is formed.

8. The method of claim 6, wherein
the optical filter element (7) is arranged on the dielectric layer (6) after the through-substrate via (5) is formed.

9. The method of one of claims 6 to 8, further comprising:

arranging an integrated optical filter layer (12) in the dielectric layer (6), the integrated optical filter layer (12) being formed as a nanooptics filter.

10. The method of claim 9, wherein
the integrated optical filter layer (12) is formed before the through-substrate via (5) is formed.

Ansprüche

1. Halbleiterbauteil zur Erfassung von Strahlung, Folgendes umfassend:

- ein Halbleitersubstrat (1) mit einer Hauptfläche (11),

- eine dielektrische Schicht (6), die mindestens eine Verbindung aus einem Halbleitermaterial umfasst, wobei die dielektrische Schicht (6) auf oder über der Hauptfläche (11) angeordnet ist,

- eine integrierte Schaltung (2), die mindestens eine strahlungssensitive Komponente (3) enthält, wobei die integrierte Schaltung (2) im Substrat (1) an oder nahe der Hauptfläche (11) angeordnet ist,

- eine Verdrahtung (4) der integrierten Schaltung (2), wobei die dielektrische Schicht (6) eine Intermetall-Dielektrikumschicht (8) umfasst, wobei die Verdrahtung (4) in der Intermetall-Dielektrikumschicht (8) angeordnet ist,

- eine elektrisch leitfähige Substratdurchgangskontaktierung (5), welche die Verdrahtung (4) kontaktiert, und

- ein optisches Filterelement (7), das unmittelbar auf der dielektrischen Schicht (6) über der strahlungssensitiven Komponente (3) angeordnet ist,

dadurch gekennzeichnet, dass

- die dielektrische Schicht (6) eine Passivierungsschicht (9) zumindest über der Substratdurchgangskontaktierung (5) umfasst,

- die Passivierungsschicht (9) ein dielektrisches Material umfasst, das sich von der Intermetall-Dielektrikumschicht (8) unterscheidet,

- die Verdrahtung (4) zwischen der Hauptfläche (11) und der Passivierungsschicht (9) angeordnet ist,

- die Passivierungsschicht (9) in oder auf der Intermetall-Dielektrikumschicht (8) angeordnet ist,

- die Passivierungsschicht (9) eine Öffnung (13) über der strahlungssensitiven Komponente (3) umfasst, wobei die Intermetall-Dielektrikumschicht (8) in der Öffnung (13) frei von der Passivierungsschicht (9) ist, und

- das optische Filterelement (7) auf der Intermetall-Dielektrikumschicht (8) über oder in der Öffnung (13) der Passivierungsschicht (9) angeordnet ist.

2. Halbleiterbauteil nach Anspruch 1, wobei das optische Filterelement (7) eine erste strukturierte Filterschicht (28), die ein Interferenzfilter bereitstellt, und eine zweite strukturierte Filterschicht (29) umfasst, die mindestens eine Farbkomponente eines RGB-Filters bereitstellt.

3. Halbleiterbauteil nach Anspruch 1 oder 2, darüber hinaus umfassend:

eine integrierte optische Filterschicht (12) in der dielektrischen Schicht (6), wobei die integrierte optische Filterschicht (12) zwischen der strahlungssensitiven Komponente (3) und dem optischen Filterelement (7) und in einem Abstand (30) vom optischen Filterelement (7) angeordnet ist.

4. Halbleiterbauteil nach einem der Ansprüche 1 bis 3, wobei Metallschichten der Verdrahtung (4) und der integrierten optischen Filterschicht (12) in der Intermetall-Dielektrikumschicht (8) angeordnet sind, und
die integrierte optische Filterschicht (12) in einer Metallschicht ausgebildet ist, die in der Intermetall-Dielektrikumschicht (8) angeordnet ist.

5. Halbleiterbauteil nach einem der Ansprüche 1 bis 4, wobei das Substrat (1) und die dielektrische Schicht (6) zusammen eine Dicke (d) von weniger als 250 µm haben.

6. Verfahren zum Erzeugen eines wie in Anspruch 1 definierten Halbleiterbauteils zur Erfassung von Strahlung, Folgendes umfassend:

- Vorsehen eines Halbleitersubstrats (1) mit einer integrierten Schaltung (2), die mindestens eine strahlungssensitive Komponente (3) enthält, an oder nahe einer Hauptfläche (11),

- Anordnen einer dielektrischen Schicht (6), die mindestens eine Verbindung aus einem Halbleitermaterial umfasst, auf oder über der Hauptfläche (11),

- Anordnen einer Verdrahtung (4) der integrierten Schaltung (2) in der dielektrischen Schicht (6),

- Ausbilden einer elektrisch leitfähigen Substratdurchgangskontaktierung (5), welche die Verdrahtung (4) kontaktiert, von einer der Hauptfläche (11) entgegengesetzten Rückseite (10) her, und

- Anordnen eines optischen Filterelements (7) unmittelbar auf der dielektrischen Schicht (6) über der strahlungssensitiven Komponente (3),

dadurch gekennzeichnet, dass

- die dielektrische Schicht (6) so ausgebildet wird, dass sie eine Intermetall-Dielektrikumschicht (8) und eine Passivierungsschicht (9) enthält, wobei die Passivierungsschicht (9) mit einer Öffnung (13) über der strahlungssensitiven Komponenten (3) versehen wird, wobei die Intermetall-Dielektrikumschicht (8) in der Öffnung (13) frei von der Passivierungsschicht (9) ist,

- die Passivierungsschicht (9) ein dielektrisches Material umfasst, das sich von der Intermetall-Dielektrikumschicht (8) unterscheidet,

- die Verdrahtung zwischen der Hauptfläche (11) und der Passivierungsschicht (9) angeordnet wird, und

- das optische Filterelement (7) auf der Intermetall-Dielektrikumschicht (8) über oder in der Öffnung (13) der Passivierungsschicht (9) angeordnet wird.

7. Verfahren nach Anspruch 6, wobei
das optische Filterelement (7) auf der dielektrischen Schicht (6) angeordnet wird, bevor die Substratdurchgangskontaktierung (5) ausgebildet wird.

8. Verfahren nach Anspruch 6, wobei
das optische Filterelement (7) auf der dielektrischen Schicht (6) angeordnet wird, nachdem die Substratdurchgangskontaktierung (5) ausgebildet wurde.

9. Verfahren nach einem der Ansprüche 6 bis 8, darüber hinaus umfassend:

Anordnen einer integrierten optischen Filterschicht (12) in der dielektrischen Schicht (6), wobei die integrierte optische Filterschicht (12) als Nanooptik-Filter ausgebildet ist.

10. Verfahren nach Anspruch 9, wobei
die integrierte optische Filterschicht (12) ausgebildet wird, bevor die Substratdurchgangskontaktierung (5) ausgebildet wird.

Revendications

1. Dispositif semiconducteur pour une détection de radiation, comprenant:

- un substrat semiconducteur (1) présentant une surface principale (11),

- une couche de diélectrique (6) comprenant au moins un composé d'un matériau semiconducteur, la couche de diélectrique (6) étant agencée sur ou au-dessus de la surface principale (11),

- un circuit intégré (2) incluant au moins un composant sensible à la radiation (3), le circuit intégré (2) étant agencé dans le substrat (1) au niveau ou près de la surface principale (11),

- une filerie (4) du circuit intégré (2), la couche de diélectrique (6) comprenant une couche de diélectrique intermétallique (8), la filerie étant agencée dans la couche de diélectrique intermétallique (8),

- une interconnexion verticale de substrat (5) électriquement conductrice qui est en contact avec la filerie (4), et

- un élément de filtre optique (7) agencé immédiatement sur la couche de diélectrique (6) au-dessus du composant sensible à la radiation (3),

caractérisé en ce que

- la couche de diélectrique (6) comprend une couche de passivation (9) au moins au-dessus de l'interconnexion verticale de substrat (5),

- la couche de passivation (9) comprend un matériau diélectrique qui est différent de la couche de diélectrique intermétallique (8),

- la filerie (4) est agencée entre la surface principale (11) et la couche de passivation (9),

- la couche de passivation (9) est agencée dans ou sur la couche de diélectrique intermétallique (8),

- la couche de passivation (9) comprend une ouverture (13) au-dessus du composant sensible à la radiation (3), la couche de diélectrique intermétallique (8) étant exempte de la couche de passivation (9) dans l'ouverture (13), et

- l'élément de filtre optique (7) est agencé sur la couche de diélectrique intermétallique (8) au-dessus ou dans l'ouverture (13) de la couche de passivation (9).

2. Le dispositif semiconducteur de la revendication 1, sachant que l'élément de filtre optique (7) comprend une première couche de filtre structurée (28) fournissant un filtre d'interférence et une deuxième couche de filtre structurée (29) fournissant au moins une composante de couleur d'un filtre RVB.

3. Le dispositif semiconducteur de la revendication 1 ou 2, comprenant en outre:

une couche de filtre optique intégrée (12) dans la couche de diélectrique (6), la couche de filtre optique intégrée (12) étant agencée entre le composant sensible à la radiation (3) et l'élément de filtre optique (7) et à une distance (30) de l'élément de filtre optique (7).

4. Le dispositif semiconducteur de l'une des revendications 1 à 3, sachant que des couches métalliques de la filerie (4) et la couche de filtre optique intégrée (12) sont agencées dans la couche de diélectrique intermétallique (8), et
la couche de filtre optique intégrée (12) est formée dans une couche métallique qui est agencée dans la couche de diélectrique intermétallique (8).

5. Le dispositif semiconducteur de l'une des revendications 1 à 4, sachant que le substrat (1) et la couche de diélectrique (6) ont ensemble une épaisseur (d) de moins de 250 µm.

6. Procédé de production d'un dispositif semiconducteur pour une détection de radiation, tel que défini dans la revendication 1, comprenant:

- le fait de doter un substrat semiconducteur (1) d'un circuit intégré (2) incluant au moins un composant sensible à la radiation (3) au niveau ou près d'une surface principale (11),

- l'agencement d'une couche de diélectrique (6) comprenant au moins un composé d'un matériau semiconducteur sur ou au-dessus de la surface principale (11),

- l'agencement d'une filerie (4) du circuit intégré (2) dans la couche de diélectrique (6),

- la formation d'une interconnexion verticale de substrat (5) électriquement conductrice qui est en contact avec la filerie (4) depuis une surface arrière (10) opposée à la surface principale (11), et

- l'agencement d'un élément de filtre optique (7) immédiatement sur la couche de diélectrique (6) au-dessus du composant sensible à la radiation (3),

caractérisé en ce que

- la couche de diélectrique (6) est formée pour inclure une couche de diélectrique intermétallique (8) et une couche de passivation (9), la couche de passivation (9) étant pourvue d'une ouverture (13) au-dessus du composant sensible à la radiation (3), la couche de diélectrique intermétallique (8) étant exempte de la couche de passivation (9) dans l'ouverture (13),

- la couche de passivation (9) comprend un matériau diélectrique qui est différent de la couche de diélectrique intermétallique (8),

- la filerie (4) est agencée entre la surface principale (11) et la couche de passivation (9), et

- l'élément de filtre optique (7) est agencé sur la couche de diélectrique intermétallique (8) au-dessus ou dans l'ouverture (13) de la couche de passivation (9).

7. Le procédé de la revendication 6, sachant que l'élément de filtre optique (7) est agencé sur la couche de diélectrique (6) avant que l'interconnexion verticale de substrat (5) soit formée.

8. Le procédé de la revendication 6, sachant que l'élément de filtre optique (7) est agencé sur la couche de diélectrique (6) après que l'interconnexion verticale de substrat (5) soit formée.

9. Le procédé de l'une des revendications 6 à 8, comprenant en outre:

l'agencement d'une couche de filtre optique intégrée (12) dans la couche de diélectrique (6), la couche de filtre optique intégrée (12) étant formée comme filtre de nano-optique.

10. Le procédé de la revendication 9, sachant que la couche de filtre optique intégrée (12) est formée avant que l'interconnexion verticale de substrat (5) soit formée.

Drawing